1. Field of the Invention
This invention relates to cellular mobile antennas for vehicles.
2. Prior Art
For AM/FM B.C. and cellular mobile telephone (MT) in vehicles, more than two antennas are usually necessary. However, an AM-FM-MT tri-band antenna is desired and one with coils is used presently.
The tri-band antenna, as shown in FIG. 1 is usually connected to an AM/FM receiver and a mobile telephone receiver/transmitter via a branching filter. Transmission loss in the branching filter and the coaxial transmission line is about 1.5-2.0 dB in all. Therefore, it is desired that the tri-band antenna has a directive gain high enough to compensate for it's loss. In addition, the tri-band antenna is required to have a directivity broad enough to keep a sensitivity in the mobile telephone band even when the antenna inclines. The tri-band antenna referred to in this application is for U.S.A. (Transmitting frequency range of MT:825-845 MHz Receiving frequency range of MT:870-890 MHz, etc.).